1. Field of the Invention
The present invention relates to valve assemblies and to domestic faucets for example.
2. Description of the Prior Art
U.S. Pat. No. 595,061 to Gulland relates to water valves.
Gulland discloses a faucet in which a ball resting on a valve seat is controlled by a flexible diaphragm. The diaphragm in turn is controlled by the pressure in a chamber. The chamber has upstream and downstream control valves which are rigidly coupled together for simultaneous operation.
When the faucet is shut off the upstream control valve is open and the downstream control valve is closed. When the faucet is fully open the upstream control valve is closed and the downstream control valve is open.
When the faucet is partially open both upstream and downstream valves are partially open allowing a continuous through flow of water, even under steady state flow conditions from the faucet.
The present invention is distinguished over the cited art in that both control valves are independently operable so that under steady state conditions for any degree of flow from the faucet both control valves are always closed.
With this arrangement for any flow rate setting of the faucet the control chamber is sealed and so has a fixed invariable volume. In this way the position of the diaphragm remains the same, irrespective of any fluctuation in the pressure of the water mains.
U.S. Pat. No. 2,222,141 to Denison discloses a gas valve.
Denison relates to a three-way pilot gas valve in which two control valves are coupled together for simultaneous operation. Neither control valve can move independently of the other.
It is an object of the invention to provide an improved valve assembly. In particular it is an object of the invention to provide a faucet in which the inlet and outlet control valves are independently operable so that the setting of the faucet can be adjusted to achieve any selected constant flow rate from the faucet.